Serum amyloid A protein monitoring for early prediction of kidney allograft rejection.

Dr. Martin T. Časl, Nova Ves 36, 41000 Zagreb (Croatia) Dear Sir, Early recognition of allograft rejection remains a major problem in clinical renal transplantation. Monitoring of inflammatory responses in the postgrafting period [1-3] provides valuable information on the rejection process. Although some 30 plasma proteins increase in concentration during inflammation, only two of them are suitable markers of acute-phase response: serum amyloid A protein (SAA) and C-reactive protein (CRP) [4-6]. Both are quick to respond and both increase substantially in severe inflammation, SAA being the more sensitive parameter [4, 6-8]. Routine assays for SAA were not available until recently, mainly due to the difficulty in producing useful antisera against human SAA. A new micro-ELISA test [9] with commercially available sequence-specific antibody obtained from Ti-noLab Co., Zagreb, Croatia [10] now enables one to measure SAA quickly and routinely. We used this micro-ELISA assay for everyday monitoring of SAA in 17 patients (4 females and 13 males) with kidney allografts in order to facilitate an early diagnosis of rejection. Altogether 43 SAA peaks were observed and 19 of them were caused by allograft rejections. The results are presented in figure 1. During the first 3 of 4 days, the initial SAA peaks (caused by surgical trauma) 400-, a